This invention relates to a method which utilizes a novel class of textile products which can be prepared from various base oils, such as mineral oil, synthetic oils, including poly-alpha-olefins and esters, silicone fluids, waxes and the like. Special decomposable emulsifiers are used in place of conventional emulsifiers. This application discloses a method for processing textile products wherein decomposable emulsifiers are used in lubricating or softening compounds to lubricate or soften textile materials by the exhaustion process wherein the emulsifiers gradually decompose into non-surface active components. The lubricant or softener applied to the yarn facilitates subsequent unwinding, and knitting or weaving operations.
As used herein, the terms "decomposable", "degradable" and "splittable" are intended to be interchangeable and generally refer to the process by which the hydrophobic and hydrophilic segments of the emulsifiers are "delinked" by hydrolysis or other chemical reaction into two non-emulsifying components. Reactions of this type are described in European Patent Nos. 742177 and 742178.
These unique lubricant and softener products may be either oil-based, i.e., with the special decomposable emulsifiers dissolved in the oil with no significant water in the products but dilutable in water to form an emulsion, or water-based emulsions with the oil-phase emulsified in water.
Lubricant and softener compounds are typically applied by the exhaust application method onto yarn, fabric, or garments by diluting the compound in a water-based bath along with the textile substrate and heating the bath to an appropriate temperature at an appropriate pH. They can also be applied by direct application, e.g., by use of a kiss roll, during coning or texturing, or onto sewing thread.
Essentially all current technology textile lubricants and softeners, especially coning and texturing oils used as lubricants, are made using conventional nonionic emulsifiers, such as nonylphenol ethoxylates and alkyl-alcohol ethoxylates. These conventional nonionic emulsifiers can contribute to dye-bleeding. In other words, residual emulsifiers contained in the lubricant applied to the dyed yarn can solubilize the dyes with which they come into contact and cause them stain adjacent, differently-colored yarns or fabric. In addition, when conventional lubricants are exhaust applied, the rate of exhaustion (or "strike rate") can only be controlled by the temperature and rate of temperature rise of the application bath.
As the application bath temperature is increased, conventional nonionic emulsifiers become less soluble as they reach their "cloud-point" temperature. This results in the oil emulsion "breaking" and the oil depositing on the textile substrate, as desired. If the exhaustion is not controlled properly, uneven amounts of lubricant are distributed throughout the yarn package from too fast a strike rate, or not enough lubricant is applied because of insufficient exhaustion.
When, as described herein, decomposable emulsifiers are used to make such lubricants or softeners, at least two significant technical advantages result:
First, When the emulsifiers are decomposed--for example during exhaust application--the decomposition products are no longer surface active, and are no longer capable of solubilizing dyes to cause bleeding or staining. In one preferred embodiment as disclosed herein, such a lubricating compound gradually decomposes when the lubricant application bath is below pH 5. Thus by using an acidic application bath, these emulsifiers gradually decompose into non-surface active species, and the oil phase gradually, yet completely, exhausts onto the textile substrate. For additional control of the exhaustion rate, an acid donor can be used in the application bath. These acid donor additives are typically hydrolyzable compounds that also gradually decompose in the hot water application baths to produce acidic residues to gradually drop the pH during the process cycle.
Second, such acid-degradable emulsifiers add an entirely new controlling mechanism to the exhaustion process. In accordance with the invention disclosed herein, both pH and temperature can be used to optimize exhaustion of the lubricant or softener onto the textile product.
Exhaust application of such textile lubricants is particularly important for "direct ship" yarns. In direct ship applications, the lubricant is applied during a package dyeing operation, and is, in fact, an integral part of the dyeing process. After completion of the dyeing operation, while the yarn packages are still in the package dyeing machine, the lubricant product is added to the final dye-bath rinse water and then exhaust applied by appropriate heating. When this lubricant application process is finished, the lubricated yarn packages are removed from the dye machine while still mounted on their plastic spools, dried, and shipped to customers for knitting or weaving. The direct ship process eliminates the steps of unwinding the dyed yarn packages, applying a lubricant, such as by kiss roll, and then rewinding onto cones for shipment to knitters and weavers.
The textile lubricants and softeners of this invention utilizing decomposable/degradable emulsifiers are particularly useful for exhaust applications because the exhaustion rate can be better controlled by adjusting both heat and pH for more level and complete application.
At the end of the process, no emulsifiers are left behind in the oil to cause dye-bleeding or "fogging." Fogging refers to the translucent film that forms on the inside of an automobile's windshield from volatile components in the car's interior, such as from dash boards, seat upholstery, headliner fabric, etc. Yarns and fabrics destined for automobile interiors are required to be "non-fogging." In other words, the fabric must not give off volatile substances which condense on the inside surfaces of the glass windshield and windows. Thus, the product and invention according to this application present several significant advantages over prior art lubricants and softeners.